In many ways photographer Mary Ellen Mark has led a charmed life. A photojournalist by trade, she’s perhaps best known for her series on street kids for Life magazine which became the seed for the documentary film “Streetwise” that she directed alongside her husband Martin Bell.

She’s photographed injustices all over the world, traveling to India, Turkey, and many parts of Africa. But in order to fund her passion she needed a more profitable “day job.”

She found that job in Tinseltown, documenting life on movie sets at a different angle from the director’s camera.

I loved it when you could just walk around with a Leica and do documentary pictures. Most often now they prefer technical portraits of the actors which they use as posters. They don’t hire you for long periods of time anymore. I was able to work on Francis Ford Coppola’s ‘Apocalypse Now’ for a month, and on Federico Fellini’s ‘Satyricon’ for a month… just to be on the set and take pictures.

While taking photos of Hollywood stars was her “day job,” it also had a profound effect on her documentary work. After being assigned to “One Flew Over the Cuckoo’s Nest” Mark returned to live in the Oregon State Hospital for more than a month, documenting the life of the women confined to maximum security in Ward 81.

The way she took photographs changed, too.

I’ve been able to watch incredibly talented people work. I’ve learned a lot watching cinematographers and how they light, costume designers and styling, how important that is. Actors taught me how important expression and mood is; directors showed me how important it is to control all that and, when I have a portrait assignment, how to work with people and tell them what to do. I’m watching great artists at work – so I’m lucky.

Mark says ultimately, whether on the set or on the street, she’s looking for the same thing – a moment that’s “graphic and that tells a story and that has an edge to it – I’m always looking for that edge.”

A devout traditionalist, Mark still works with analog film and a Leica camera and refuses to crop her pictures. At 73, she says she’s “out of shape” when it comes to street photography, but her appetite for social justice hasn’t diminished. She recently finished a project looking at healthcare for children around the globe.

“It’s made me want to do more projects photographing children, and doing more health care stories,” said Mark. “It changed my life and how I want to look at things.”